This invention relates generally to air intakes for engines, and in particular to a system for readily installing and mounting barrier filters across an intake passage to protect an aircraft engine.
An engine for aircraft propulsion requires intake air that is free from contaminants to provide for efficient combustion and avoid internal damage. The compressor and turbine are designed with small tolerances between moving parts which maximize efficiency, but which also increase vulnerability to damage from small foreign particles. Contamination of intake air, even in a small amount, causes premature wear on engine components, increases maintenance costs, and degrades operational reliability. Unfortunately, aircraft are exposed to contaminants when operating at low altitudes where air is frequently contaminated with material from the ground, such as sand and dust. That problem is aggravated for helicopters due to rotor downwash and prolonged low-altitude operation.
Systems which remove foreign particles from intake flow have been developed to protect the engine from damage. These systems include a contaminant separator positioned in advance of the engine. Unfortunately, it is frequently difficult to access the contaminant separator for periodic maintenance tasks. Typically, the intake passage and adjacent area have tightly limited space constraints which restrict accessibility. The separator may have a relatively large size extending across an entire width of the passage so as to receive all intake air. Removal or replacement of the separator requires substantial disassembly and subsequent re-assembly of surrounding parts. These steps are inefficient and degrade operational readiness. Further, some systems fail to provide an auxiliary or bypass flow path enabling continued operation of the engine with an adequate quantity of air should the separator become plugged with contaminants.